contraction of "Geoff Fresh", or "Geoffrey Fresh", sometimes used as G (Fresh), it is used as a nom de plume to indicate a strong tongue-in-cheek response or recommendation or assignment or attribution to the author, one who is named "Geoff" or "Geoffrey". One can also use a mitigated version, as in "G (fresher than most)". The usages are an intellectualization of Geoff's emotional or intentional states of mind when presented as a salutation and authorship.

In a letter to a friend, example:
(discussing Apple's new phone product release)

What do you mean, "almost complete"?

Hell, they're sucking out your bodily fluids while you sleep for their alien experiments... Pretty soon, you'll wake up and say, " Steve IS my savior, no one else maketh me to lie down in green pastures..."

What is next? Perhaps the latest Apple 'next great thing'? A smart TV? .... Electrode implantation?

You just need to clone the whole family for the almighty fruit, blessed be it! Apple suite of products for everyone!!